started thinking about macros

macros/builtins.go

@@ -0,0 +1,10 @@
+package macros
+
+import (
+	"github.com/mediocregopher/ginger/macros/pkgctx"
+	"github.com/mediocregopher/ginger/types"
+)
+
+func Package(p *pkgctx.PkgCtx, el types.Elem) string {
+	return ""
+}

macros/macros.go

@@ -0,0 +1,30 @@
+package macros
+
+import (
+	"fmt"
+	"os"
+	"time"
+
+	"github.com/mediocregopher/ginger/macros/pkgctx"
+	"github.com/mediocregopher/ginger/types"
+)
+
+// A Macro takes in a ginger structure and returns the go code which corresponds
+// to it. The structure will contain everything in the calling list after the
+// macro name (for example, (. jkjkNo error is returned, Bail can be called to stop compilation mid-way
+// instead.
+type Macro func(*pkgctx.PkgCtx, types.Elem) string
+
+// Bail stops compilation. The given element should be the reason compilation
+// has stopped
+func Bail(el types.Elem, reason string) {
+	fmt.Fprintln(os.Stderr, reason)
+	time.Sleep(100 * time.Second)
+	os.Exit(1)
+}
+
+// Bailf is like Bail, but takes in formatting
+func Bailf(el types.Elem, format string, args ...interface{}) {
+	reason := fmt.Sprintf(format, args...)
+	Bail(el, reason)
+}

macros/pkgctx/pkgctx.go

@@ -0,0 +1,18 @@
+package pkgctx
+
+// PkgCtx is given to all macros and represents the package that they are being
+// evaluated within.
+type PkgCtx struct {
+
+	// Packages describes the external packages imported by this one. Each key
+	// is the absolute package path, the value is the alias for it (or empty
+	// string for no alias)
+	Packages map[string]string
+
+	// CallDict is a map used by Eval for making actual calls dynamically. The
+	// key is the string representation of the call to be used (for example,
+	// "fmt.Println") and must agree with the aliases being used in Packages.
+	// The value need not be set during actual compilation, but it is useful to
+	// use it during testing
+	CallDict map[string]interface{}
+}